The attacks on Monday have prompted countries throughout Europe to beef up their security.

France's government has heightened security at Christmas markets around the country. Interior Minister Bruno Le Roux ordered security forces to be extra vigilant and added that 3,000 more personnel will be deployed during the upcoming holidays.

Police officers patrol at a Christmas market along the Champs-Elysees in Paris, capital of France, on Dec. 20, 2016. French Interior Minister Bruno Le Roux on Monday decided to reinforce security at France's Christmas markets and maintain high vigilance after the Berlin attack which caused scores of casualties. (Xinhua/Chen Yichen)

Neighboring Italy is also strengthening security measures for areas where crowds are expected to gather for Christmas ceremonies. This includes markets and concert halls, as well as institutional buildings and embassies.

And London police say they are reviewing their plans for protecting the public at events during the course of the festive period.